IP or Not?

How it works

Every day there are five new questions, the same for everyone on that date. Answer them all to keep your streak going. After each answer you see why it was right or wrong, with a link to a guide if you want to read more. When you finish, play as many practice rounds as you like. They don't affect your streak.

There's no timer, and you can use the number keys 1 to 4 to choose an answer.

What the questions cover

• Spot the typo: is this a correctly written IPv4 address?
• What kind of address? Private, public, loopback, self-assigned, carrier-shared, or reserved for examples. See public vs private IP addresses.
• IPv6 check: which of these is valid? See IPv4 vs IPv6.
• Same network? Do two addresses share a subnet? Try the subnet calculator to explore.
• Real world: what does an address tell you about a problem on your own network?

Rules worth remembering

• An IPv4 address is four numbers from 0 to 255, separated by dots.
• Private addresses start with 10., 172.16 to 172.31, or 192.168. A 172.32 address is public.
• 127.x.x.x is the device itself. 169.254.x.x means the device couldn't get an address from the router.
• 100.64 to 100.127 is shared by internet providers for CGNAT.
• An IPv6 address has eight groups of up to four hex digits, and :: can stand in for a run of zeros once.
• Two devices share a network when their addresses match across the subnet's prefix, for example the first 24 bits of a /24.

Rewards for Pip

Score 5 out of 5 in any round to earn the IP whiz sticker and a graduation cap for Pip. Open Pip's speech bubble and choose Dress Pip to wear it.

Accessibility and privacy

The quiz uses real buttons, works with a keyboard and a screen reader, and has no time limit. Your streak and best score stay in your browser. Nothing is sent to us.